JP2004522171A - Method and apparatus for locating a transmitter and a mobile communication device - Google Patents

Abstract

A method is disclosed for locating a transmitter (BS1) located near a mobile communication device (MS1) that can determine its own location. The method comprises: (i) moving a mobile communication device (MS1) to a plurality of reference positions (pn); and (ii) the position of the mobile communication device (MS1) and each of the mobile communication device (MS1) from the mobile communication device (MS1). Determining a distance to a transmitter (BS1) at a reference position (pn); and (iii) using the position identified in step (ii) and the corresponding distance to determine the distance of the transmitter (BS1). Identifying a position. A method for locating a mobile communication device (MS1) that utilizes the above method is also disclosed.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and a corresponding device for locating a transmitter and a related method and a corresponding device for locating a mobile communication device.
[0002]
In order to provide a GPS fix, a typical GPS receiver needs to receive at least four GPS signals and must therefore have at least four observable GPS satellites. Unfortunately, however, it can often occur that at any one time fewer than four satellites are observable in an overgrown area or urban canyon. Furthermore, the number of observable satellites can change rapidly when the GPS receiver is moving, for example when a user is traveling in a car.
[0003]
[Prior art]
Providing a mobile cell phone with a built-in GPS receiver, as well as supplementing the mobile phone and the pseudorange obtained by the GPS receiver to achieve position determination when there are fewer than four observable satellites The use of a ranging measurement with a mobile network base station with which it is registered is disclosed at least in the related US Pat. Nos. 5,982,324, 6,236,359 and 6,249,245. Are known. In the device, the position of the base station is required to be known, and if the position of the mobile phone is specified by phone, the position of the base station may be transmitted to the phone. Needed. However, if the location of the base station is not known, or if the location of the base station is not transmitted to the mobile phone when the location is specified on the phone, the The ranging in between is useless.
[0004]
[Problems to be solved by the invention]
Accordingly, it is an object of the present invention to provide a method and corresponding apparatus for locating a transmitter located in the vicinity of a mobile communication device, and further for locating said mobile communication device. A related method and a corresponding device.
[0005]
[Means for Solving the Problems]
According to a first aspect of the present invention, a method for locating a transmitter is provided when said transmitter is located near a mobile communication device capable of locating itself. The present invention provides (i) moving the mobile communication device to a plurality of reference locations; and (ii) at each reference location, the location of the mobile communication device and the transmission from the mobile communication device. Determining the distance to the transmitter; and (iii) determining the position of the transmitter using the position and the corresponding distance specified in step (ii).
[0006]
For the purpose of answering the question, the "reference position" is not intended to convey the meaning that said position is determined by some means or has been pre-specified, but rather in step (ii) itself. Once the position of is determined, it is intended to convey the meaning that the position of the transmitter will be the reference position specified in step (iii).
[0007]
The method allows the location of the transmitter to be determined, which may then be used as a reference to further locate the mobile communication device. Thus, according to a second aspect of the present invention, there is provided a method of locating a mobile communication device, comprising: (a) being located near said mobile communication device by the method according to the first aspect of the present invention. Locating at least one transmitter; (b) determining a distance from the mobile communication device to the or each transmitter; and (c) determining at step (a). Locating the mobile communication device using the or each transmitter's location and the or each distance identified in step (b).
[0008]
The location of the mobile communication device in step (ii) may be located using a GPS receiver, wherein the location of the mobile communication device is located in a GPS receiver, the location being identified in step (a). It may be specified in step (c) using a combination of the transmitter or the position of each transmitter and the pseudo-range obtained using the or each distance specified in step (b). This is advantageous if during the step (c) the GPS receiver cannot achieve an unambiguous position fix itself.
[0009]
The invention also provides a mobile communication device according to any one of claims 9 to 13.
[0010]
An apparatus embodying the method of positioning according to the invention will now be described by way of example only with reference to the accompanying drawings.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The geographical layout of a conventional GSM mobile telephone network 1 is schematically illustrated in FIG. The network has a plurality of base stations BS, and shows seven base stations, BS1 to BS7, each located at a geographical location spaced apart from one another. Each of the base stations has a set of wireless transmitters and receivers operated by a trunking system controller at any one site or service area. The service areas SA1 to SA7 of the base station overlap as shown by cross-hatching to collectively cover the entire area shown. The system may further comprise a system controller SC with a two-way communication link (CL1 to CL7 for base stations BS1 to BS7 respectively). Each of the communication links may be, for example, a dedicated land-line. The system controller SC may be further connected to a public switched telephone network (PSTN) so as to enable communication between the mobile cellular phone MS1 and a subscriber to the network. A plurality of mobile telephones MS are provided, three of which are shown, MS1, MS2 and MS3. Each of the mobile telephones is free to roam across the entire area and, in fact, outside the area.
[0012]
FIG. 2 shows a communication transmitter and receiver (Comm Tx / Rx) 20 connected to a communication antenna 21 and controlled by a microprocessor (μc) 22 for communication with a registered base station BS1. 2 shows the configuration of the mobile telephone MS1 having the following in more detail. The design and manufacture of such telephones for two-way communication in a cellular telephone network is well known, and parts that do not themselves form part of the present invention will not be further described in this case.
[0013]
In addition to the conventional components of a mobile phone, the phone MS1 is connected to a GPS antenna 24 to receive a GPS spread spectrum signal transmitted from an orbiting GPS satellite, and to a micro antenna. It further has a GPS receiver (GPS Rx) 23 controlled by a processor (μc) 22. In operation, the GPS receiver 24 may receive a NAVSTAR SPS GPS signal via a GPS antenna, out-of-band RF interference, pre-amplification, intermediate frequency band ( The signal may be pre-processed, typically by passive bandpass filtering to minimize down conversion to analog frequency (IF) and analog-to-digital conversion. The resulting digitized IF signal is kept modulated while still containing all information from the available satellites and is input to the microprocessor memory (not shown). The GPS signal is then acquired on any of a plurality (typically up to 12) of digital receiver channels to obtain pseudorange information from which a mobile phone can be located using conventional navigation algorithms. ) And may be tracked. The method of capturing and tracking GPS signals is described, for example, in "GPS Principles and Applications" (by Kaplan), ISBN 0-89006-793-7, Chapter 4 of Arttech House. (GPS satellite signal characteristics) and Chapter 5 (GPS satellite signal acquisition and tracking). The general purpose microprocessor 22 shown controls both base station communications and GPS processing, but alternative processing architectures are used to achieve the same result, such as those using separate communications and GPS ICs. It will be appreciated that it may be.
[0014]
Hereinafter, identification of the position of the base station will be described. Referring to FIG. 3, the base station BS1 is located at an unrecognized coordinate ( _xbs1 , _ybs1 , _zbs1 ). The mobile phone MS1 has a GPS receiver and may use a GPS receiver at n different positions (pn) with coordinates (x _pn , y _pn , z _pn ) to achieve position determination. At that location, the mobile telephone MS1 can communicate with its registered base station BS1 in such a way as to be able to realize a range measurement (r _pn-bs1 ) with _respect to the base station BS1. Given a position fix and corresponding distance measurements at three different positions, the position of the base station BS1 can be determined by solving the following simultaneous equations.
^{_{(R p1-bs1) 2 =}} (x bs1 -x p1) 2 + (y bs1 -y p1) 2 + (z bs1 -z p1) 2
^{_{(R p2-bs1) 2 =}} (x bs1 -x p2) 2 + (y bs1 -y p2) 2 + (z bs1 -z p2) 2
^{_{(R p3-bs1) 2 =}} (x bs1 -x p3) 2 + (y bs1 -y p3) 2 + (z bs1 -z p3) 2
[0015]
While the above equation requires three position determinations and corresponding distance measurements, it can be assumed that the altitude of the base station BS1 and the positions p1 and p2 are the same. In this case, only two position determinations and corresponding distance measurements, performed at positions p1 and p2, are needed to determine the position of base station BS1. Similarly, at different locations, four or more location determinations and corresponding distance measurements can be made, thereby over-determined, which can be solved using the optimal type of method. A set of over-determined set of equations results. If spur location and distance measurement are appropriate, the reliability of the method can be even higher.
[0016]
Hereinafter, identification of the position of the transmitter will be described. Using the method described above, the location of any mobile network base station can be determined. Thereby, subsequent distance measurements can be used to locate the mobile unit.
[0017]
Referring to FIG. 4, the mobile phone MS1 has previously identified, unrecognized coordinates of nearby base stations BS1, BS2, and BS3 having coordinates ( _xbsn , _ybsn , _zbsn ). (X _ms , y _ms , z _ms ). From the base station, the mobile phone MS1 communicates with the base station in such a way that a distance measurement ( _rms-bsn ) to the base station can be achieved and therefore the location of the mobile phone MS1 can be determined. be able to. For example, the distance measurement can be obtained by solving the following simultaneous equations.
^{_{(R p1-bs1) 2 =}} (x bs1 -x ms) 2 + (y bs1 -y ms) 2 + (z bs1 -z ms) 2
^{_{(R p2-bs1) 2 =}} (x bs2 -x ms) 2 + (y bs2 -y ms) 2 + (z bs2 -z ms) 2
^{_{(R p3-bs1) 2 =}} (x bs3 -x ms) 2 + (y bs3 -y ms) 2 + (z bs3 -z ms) 2
[0018]
Assumptions are again made to reduce the number of base station localization and distance measurements required. Further identification may also be made to yield an over-determined set of equations that can be solved using optimal methods. Still alternatively, a conventional time difference of arrival (TDOA) positioning technique may be used to determine the location of the mobile unit MS1.
[0019]
In the above example, ranging to the base station at previously unknown locations is used as a complete alternative to GPS positioning, but is not necessary in this case. For example, when the GPS receiver of MS1 is capable of observing four GPS satellites at three separate locations, the mobile phone MS1 may conveniently be located at a single registered base station. Then, if one of the GPS satellite signals is lost, eg, when entering a city canyon, the ranging for the single base station will be a pseudorange derived from the remaining GPS signals to achieve a new position fix. Can be used to supplement
[0020]
As an alternative to a GPS receiver, a conventional terrestrial based positioning system may be used to provide a location pn which is used to locate the base station. For example, the mobile phone MS1 may be brought into a network of short range information beacons that broadcast its location. If within a certain beacon range, the broadcasted location can be used to estimate the location pn of the mobile phone MS1.
[0021]
While the invention has been described primarily with reference to the commercial use of mobile phone positioning, it will be appreciated that other devices, including dedicated positioning units, may use the positioning method.
[0022]
From reading the present disclosure, other variations will be apparent to persons skilled in the art, and will be apparent to those skilled in the art in designing, manufacturing, and using both GPS receivers and mobile communication devices and their component parts. It may include features and may be used in place of or in addition to features already described herein.
[Brief description of the drawings]
FIG. 1 shows a geographical layout of the mobile phone network of the present invention.
FIG. 2 shows the configuration of the mobile cellular phone MS1 in further detail.
FIG. 3 shows the ranging between a fixed base station BS1 and a mobile telephone MS1 at positions p1, p2, p3 and p4.
FIG. 4 shows the ranging between the mobile telephone MS1 and the base stations BS1, BS2, BS3 and BS4.

Claims (13)

A method of locating a transmitter located near a mobile communication device capable of locating itself, comprising:
(I) moving the mobile communication device to a plurality of reference positions;
(Ii) identifying, at each of the reference locations, a location of the mobile communication device and a distance from the mobile communication device to the transmitter;
(Iii) using the location identified in step (ii) and the corresponding distance to determine the location of the transmitter. The method of claim 1, wherein the location of the mobile communication device is determined using a GPS receiver in step (ii). The method according to claim 1 or 2, wherein the transmitter is a mobile phone network base station and the mobile communication device is a mobile mobile phone registered with the base station. A method for locating a mobile communication device, comprising:
(A) (i) moving the mobile communication device to a plurality of reference positions;
(Ii) at each of the reference positions, the position of the mobile communication device;
And determining a distance from the mobile communication device to a transmitter;
(Iii) locating the transmitter using the location of the mobile communication device identified in step (ii) and the corresponding distance. Locating at least one transmitter located at:
(B) determining a distance from the mobile communication device to the or each of the transmitters;
(C) the mobile communication device using the location of the or each of the transmitters identified in step (a) and the or each of the distances identified in step (b). Locating a further location of the object. 5. The method of claim 4, wherein the location of the mobile communication device is determined using a GPS receiver in steps (a) (ii). The location of the mobile communication device is the GPS receiver, the location of the transmitter or each of the transmitters identified in step (a), the location identified in step (b) or 6. The method of claim 5, wherein the step (c) is identified using a combination of pseudoranges obtained using each of the distances. 7. The method according to claim 6, wherein the location of the mobile communication device in step (c) is determined when the GPS receiver cannot achieve an explicit position fix itself. The method according to any one of claims 4 to 7, wherein at least one transmitter is a mobile phone network base station and the mobile communication device is a mobile phone registered with the base station. Positioning means for specifying its own position, ranging means for specifying a distance from itself to a transmitter located nearby, its own position specified by the positioning means, and the ranging means Processing means configured to determine the location of the transmitter using the corresponding distance identified by the mobile communication device. The device according to claim 9, wherein said positioning means comprises a GPS receiver. The processing means uses the location of at least one of the transmitters identified by itself and a corresponding location or distances identified by the ranging means to further position the mobile communication device. The device according to claim 9 or 10, further configured to determine The positioning means has a GPS receiver, and the processing means is a combination of a pseudorange obtained by the GPS receiver, the position of at least one of the transmitters specified by the processing means, and the ranging means. 12. The device of claim 11, wherein the device is configured to determine a further location of the mobile communication device using a corresponding one or more distances identified by: 13. A mobile cell phone according to any one of claims 9 to 12, wherein the ranging means has the form of a mobile cell phone, capable of specifying a distance to a transmitter in the form of a cell phone network base station with which the mobile phone is registered. Devices.